The present invention relates to aerators for the treatment of liquids, and, in particular, it relates to bearing protection devices for liquid aerators.
Aerators for the treatment of liquid, and particularly water, are known in the prior art. Such treatment is employed to encourage aerobic bacteria activity, as in the treatment of waste water, for example. Such equipment may also be employed in the treatment of water bodies generally; such as to render them more potable, suitable for food production, or to return them to their natural state.
An aerator typically has a motor, a propeller carried by a motor driven shaft, a passage for airflow to the propeller, and at least one bearing to support the shaft against deflection. Over a period of time, liquid will affect the bearings. When the bearings are damaged or otherwise impaired by wear or use, they need replacement. It follows that it is beneficial to prolong the life of the bearings by reducing the effects of the liquid being aerated on the bearing. Bearing seals are generally employed for this purpose in an attempt to block liquid from the bearing. The importance of the bearing protection increases with increasing corrosiveness of the liquid being treated.
If the air passage to the propeller directs the air over or past the bearing, the air flow tends to move the liquid away from the bearings during operation of the aerator. The bearing seals must still contend with back flow and splashes as well as down times when the propeller is submerged and the unit is not operational. Other aerator designs have the bearing seals submerged even during operation. In either case, liquids can seep past the bearing seal thereby reaching the bearings. The end result is that the bearings need more frequent replacement.